High-dispersion spherical holographic gratings in a modified Rowland mounting
2001
For holographic gratings requiring an extreme dispersion, I
consider a modified Rowland mounting, in which the recording laser
sources are moved away from the grating, to reduce the uncorrected
higher-order aberrations. In addition, I choose the geometric
parameters such that first-type coma is corrected. Then a plane
multimode deformable mirror (MDM) or two auxiliary spherical
holographic gratings (R3 device) are used to aberrate the
grating’s recording sources; correction up to the fourth order is
sufficient to obtain high image quality. Applied to the FUSE–Lyman
(FUSE is Far Ultraviolet Spectroscopic Explorer) grating, with a
groove density as high as 5767 grooves/mm, these recording devices
produce a resolution (chromatic resolving power) as great as
611,000 with the MDM and 3,030,000 with the R3 device. These
results far exceed the specified performance of 30,000. Since
diffraction limits the resolution to 482,000, the images are
diffraction limited with both devices.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
9
References
4
Citations
NaN
KQI